Explain to me a little bit about the geographic significance of it gets a lot of Americans know -- -- better by its previous name Stalin grunt. What is the significance of the city -- mean beyond the these current disputes. Well absolutely so what what be what the intention. Apparently was was for these groups. To come out of the northern caucuses which is where we are we're guessing that there from if you look at. The attack that took place in -- regret in October. On a bus that killed six people it was a woman who carried out a suicide attack she was from Dagestan. Most of the attackers that we've seen have come out of three main provinces. In the north caucuses Ingushetia. Chechnya and Dagestan which incidentally was where the two bombers were from. At the Boston Marathon and so. The what they're trying to show is that you know this we can strike anywhere Volgograd is a city of one million people it's Russia's fifth largest city. They struck a train station which is one of the busiest in Russia because that connects southern Russia with northern Russia you -- you veins of of of of train of railways coming in from. All over the country. So what they're saying is is we can strike at the heart. Of of what of of you know of Russia essentially. At a time I should mention. Right before the new year of course in the states and Europe New Year's Eve is a huge holiday but takes on added significance -- Russia because. It's it's essentially. Christmas new year a real family holiday all rolled into one so that transition was especially busy -- and so that's that the message that they were trying to convey -- strike in a major city beyond our reporters at a very busy time less out of religion are you brought the Boston Marathon bombing given that kind of US connection. Have we gotten any indication that US authorities might be joining in this investigation on either of those attacks. Not just -- you have to imagine that they are watching extremely closely and trading information as we know they did in the wake. Of the Boston Marathon bombings but there's been no indication that there will be American law enforcement on the grounds. Now or or at the at the Sochi games. As I mentioned that Russia has long said that that this will be the safest Olympic Games in history so they're pulling out all the stops. Sochi will be -- surrounded and flooded with all sorts of security whether it's police paramilitary. And military so you have to imagine that they are really taking all precautions and and and so far they haven't invited any sort of outside help forty days ago and a lot of work to be done ABC's -- court in London -- thank you -- that we certainly appreciate.

This transcript has been automatically generated and may not be 100% accurate.

{"id":21371434,"title":"Terror Attacks in Russia: Significance of Volgograd","duration":"3:00","description":"Major Russian city, formerly called Stalingrad, is close to the volatile North Caucasus region.","url":"/International/video/terror-attacks-russia-significance-volgograd-21371434","section":"International","mediaType":"Default"}